December 2024
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7 Reads
The Bulletin of the Ecological Society of America
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December 2024
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7 Reads
The Bulletin of the Ecological Society of America
December 2024
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170 Reads
Agricultural areas represent one of the major ecosystems of the world. Intensification of agricultural practices produced openfields characterized by low biological diversity. Nevertheless, the distance up to which intensive agricultural fields alter surrounding natural systems is rarely quantified. We determined the spatial scale at which agricultural landscapes alter the diversity of Odonates, a key taxon in wetland ponds, and we tested to what extent citizen science data can be used reliably for this purpose. We compiled 7731 observations made in a portion of the region Centre‐Val‐de‐Loire (France) over 10 years by naturalists on 729 water bodies to analyze the effect of agricultural landscapes (mainly wheat, rapeseed, sunflower) on the species richness of both damselflies and dragonflies in lentic systems. Sixty species were reported over the 10‐year period. For dragonflies, intensive agricultural landscapes best explained their richness at the scales of 800 and 1600 m for overall and autochthonous species, respectively, when using the full dataset. The spatial scale was smaller for damselflies, at 200 m for both overall and autochthonous species. These distances were not severely impacted when constraining the data to consider several biases. Multimodel averaging showed that the proportion of intensive agriculture decreased species richness, despite the potential biases inherent to an imperfect database acquired by citizens. This imperfect citizen dataset allows to infer the lowest effect size of agriculture on species richness. Quantitatively, this effect was more important for autochthonous species. Interestingly, both relatively rare taxa and common or generalist species can be under threat in intensive agricultural landscapes, calling for more ecotoxicological studies. The influence of agricultural practices from a distance implies that conservation and management plans of wetland ponds should consider the landscape ecological characteristics and not only the pond features. Conservation efforts focusing too locally on a site may be undermined because intensive agriculture from a distance limits the potential for the site to recover highly diverse communities. These distant effects should be integrated by policy‐makers when deciding which wetland pond should benefit from a conservation plan or which conservation action may be planned, implementing, for instance, buffer zones and/or ecological corridors composed of natural vegetation.
December 2019
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244 Reads
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1 Citation
In France, Leucorrhinia albifrons is a rare species with a fragmented distribution and three areas of occupancy: in the Nouvelle-Aquitaine, in the Bourgogne-Franche-Comté and in the Pays de la Loire regions. Close to this last region, the discovery of a population in Indre-et-Loire department in June 2017 represents the first record of the species for the Centre - Val de Loire region. The conservation status of this population seems favorable regarding population size and habitat quality. Although it is still unknown wheter this population remains from an ancient bigger population or follows a recent colonization, it seems to be isolated from the other sites found in the central western part of France. Oncoming monitoring should provide new information about the population's origins.
February 2019
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538 Reads
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9 Citations
Journal of Insect Conservation
Determining how species use different habitats during critical phases of their development is one of the crucial challenges that conservation biology meets. However, habitat requirements remain unknown for most species, in particular for the rarest and most threatened which by definition are difficult to study. Here, we used animal-borne telemetry to identify the habitat of the sexually immature adults in the threatened dragonfly Leucorrhinia caudalis. We used an harmonic radar with customized tags fixed on the back of the abdomen of flying immature dragonflies to monitor their position within an area composed of various types of habitats including open areas, forest and water bodies. From 62 tagged individuals, we obtained 23 detections, all within a quite restricted area around the pond of emergence. About 75% of the detections happened in the forest canopy and the individuals were likely positioned at the top of the trees. The relatively low detection rate was probably due to high predation within the study area during the maturation phase in this dragonfly but long-range dispersal cannot be excluded. The use of forest canopy as a maturation habitat is an important knowledge for planning conservation strategies in this endangered species, especially for populations living in areas without any protection status. Although technological constraints are still limiting its efficiency, animal-borne telemetry appears to be useful to determine precisely habitat selection by rare species.
December 2012
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137 Reads
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4 Citations
Conservation of Odonata species (dragonflies and damselflies) contributes to the maintenance of biodiversity and to the functioning of natural ecosystems. They are particularly sensitive to environmental changes as they are potentially exposed to threats in both aquatic and terrestrial medium. A national plan for the conservation of Odonata species was launch in 2010 in France, with the aim to assess the population level of 18 species that were declared under threat. This national plan is downscaled here at the level of the region Centre. This regional plan reviews our knowledge on population level of several Odonata species, and suggests action plans for the period 2013-2017 in terms of increasing knowledge, conservation management and communication at several levels. This approach aims at stabilizing these threaten species in the region Centre by networking all actors in the conservation of Odonata species. The review shows that the sampling effort has increased substantially since 2000s, although it remains heterogeneous over the region Centre territory. The region Centre hosts 8 species targeted by the national plan (priority 1). In addition, the regional plan targets 13 species of priority level 2 and 9 of priority level 3. The regional plan proposes 9 actions to increase our knowledge. As specified in the national plan, the species Leucorrhinia caudalis is among the main targets of this plan. The Loire Valley is also of concern as 2 species of priority level 1, Gomphus flavipes and Ophiogomphus cecilia, are associated to this particular freshwater system. Finally, 5 actions for conservation management / administration, and 3 actions for communication and training are proposed with the aim to protect these Odonata species and their habitats. --- La préservation des Odonates (libellules et demoiselles) contribue de façon importante au maintient de la biodiversité et au bon état de conservation des écosystèmes. Les Odonates sont confrontés aux menaces environnementales dans les deux milieux, aquatiques et terrestres. Un Plan National d’Actions (PNA) en faveur des Odonates a été lancé en France en 2010. Ce plan vise à évaluer l’état de conservation de 18 espèces d’Odonates jugées menacées sur le territoire métropolitain. Ce PNA est décliné ici en région Centre. Cette déclinaison intègre une synthèse des connaissances sur l’état des populations des espèces d’Odonates visées, et propose des actions pour la période 2013 2017 en termes d’approfondissement des connaissances, de gestion conservatoire et de sensibilisation à plusieurs niveaux. Cette démarche vise à permettre, en associant les acteurs engagés dans la conservation des Odonates, le maintient en région Centre de ces espèces menacées. La synthèse générale montre que l’effort de prospection s’est intensifié depuis le début des années 2000. Cependant, cet effort est encore hétérogène sur le territoire de la région Centre. La région Centre est occupée par 8 espèces du PNA (espèces de priorité 1). Le Plan Régional d’Actions en faveur des Odonates (PRAO) incorpore également 13 espèces dites de priorité 2 et enfin 9 espèces de priorité 3. Le PRAO Centre développe 9 actions d’approfondissement des connaissances. Comme demandé dans le PNA, la Leucorrhine à large queue (Leucorrhinia caudalis) est une des cibles principales de ce plan d’actions. Le fleuve Loire constitue aussi un enjeu national pour au moins 2 espèces, le Gomphe à pattes jaunes (Gomphus flavipes) et le Gomphe serpentin (Ophiogomphus cecilia), qui sont fortement associées aux habitats particuliers à ce système fluvial. Enfin, cinq actions de gestion conservatoire / administration et 3 actions de formation et sensibilisation sont proposées dans le but général d’assurer la protection de ces espèces Odonates et de leurs habitats.
... En Europe, les données réunies depuis deux décennies illustrent les déplacements de L. albifrons et les modifications de son aire de répartition à l'échelle régionale. Elle a ainsi été observée pour la première fois en Belgique en 2016 (De Knijf & Berx 2019), de même que dans la Vallée de la Loire en 2017 (Sansault et al. 2019). En Hollande, elle a été revue en 2005, après plusieurs décennies d'absence (De Boer & Wasscher 2006). ...
December 2019
... Several animal species require distinct habitats for larval development, maturation, overwintering, foraging, and/or oviposition and depend on both aquatic and terrestrial habitats (e.g., Le Naour et al., 2019;Pope et al., 2000;Wiens, 1989). For these species, agricultural practices can directly influence the habitats used during both their terrestrial and aquatic life periods, thereby altering the services that these species can provide (Priyadarshana & Slade, 2023;Raitif et al., 2019). ...
February 2019
Journal of Insect Conservation
... However, riverine habitats and species have been poorly investigated by volunteers and these protocols have been designed to survey spatial and temporal trends in adults on a large scale but are not suitable for local riverine species surveys. Riverine species are also often neglected on the Natura 2000 sites where they are present (Costes et al., 2017) and the French action plan in favour of dragonflies identifies a need for quantitative data and calls for the development of effective standardised protocols (Dupont, 2010). ...
December 2012